Perimetry change of primary chronic glaucoma after intraocular pressure reduction

Objective: The goal of treatment for glaucoma was control of intraocular pressure (IOP) and improvement of visual function. Perimetry is one of evaluating indexs of visual function. This study was to compare the changes of visual field before and after IOP reduction in primary chronic glaucoma including primary chronic angle-closure glaucoma (PACG) and primary open angle glaucoma (POAG) and determine the factors associated with visual field changes. Methods: This is a case-observation study. Forty-four primary chronic glaucoma eyes were studied including 25 PACG eyes and 19 POAG eyes. All patients underwent regular eye examinations and visual field examination using Humphrey Field Analyzer with the program of 24-2 full threshold testing. Retinal alteration was evaluated by Heidelberg Retina Tomography-II (HRT-II). Patients received medicine, laser or surgery therapy respectively according to the status of disease. Visual field was repeatedly detected one month after the IOP declined to less than 21 mmHg. Mean defect (MD) and pattern standard deviation (PSD) were compared before and after IOP reduction in primary chronic glaucoma. The correlation of IOP reduction, age, C/D area ratio with MD changes were analyzed. Results: MD before and after IOP reduction was - 13.58 ± 9.31 and - 12.08 ± 8.37 respectively, indicating that MD was improved significantly after IOP reduction (t = 3.35, P = 0.002), but the difference of PSD showed insignificant change (7.36 ± 3.88 vs 7.67 ± 4.23, t = -1.396, P = 0.170). The changes of MD and extent of IOP reduction presented a positive correlation (r = 0.341, P = 0.027). Covariate analysis showed that no significant correlation between age or C/D with changes of MD (F = 2.267, F = 0.399, P > 0.05), but IOP reduction was still related with change of MD (F = 4.706, P = 0.037). Conclusion: Visual field is improved after IOP reduction in primary chronic glaucoma, including both POAG and PACG.